Bleach-out - method of producing line drawings from photographic images. The photographic is processed in the normal way, its outlines sketched, and the black metallic silver image is then bleached away to leave a drawn outline.

Blocked up - a portion of an overexposed and/or overdeveloped negative so dense with silver halides that texture and detail in the subject are unclear.

Blocking out - method of painting selected areas of a negative with an opaque liquid on the non-emulsion side. Since light is unable to penetrate these areas they appear white on the final print.

Borax - mild alkali used in fine grain developing solutions to speed up the action of the solution.

Boric acid - compound used in certain fixers to prolong shier hardening life.

Brightfield - method of illumination used in photomicrography which will show a specimen against a white or light background.

Brilliance - intensity of light reflected from a surface. It is sometimes an alternative term for luminosity.

Brometching - obsolete, special method of producing a bromide print. The result acquired the texture of its support and appeared similar to an etching.

Bromide paper - most common type of photographic printing paper. It is coated with an emulsion of silver bromide to reproduce black & white images.

Bromoil process - old printing process invented in 1907, consisting of three stages. First, an enlargement is made on bromide paper and processed. Second, the silver image is removed in a bleacher which also modifies the gelatin so it will accept lithographic ink. Third, while still damp the gelatin is inked up by hand to create the image.

Brush development - method of development in which developer is applied to the material with a brush or similar instrument.

Buffer - chemical substance used to maintain the alkalinity of a developing solution, particularly in the presence of bromine which is produced during development.

Butterfly lighting - lighting in which the main source of light is -placed high and directly in front of the subject.